Complete Full Disk Encryption with Lubuntu 22.04?

[kalpana]

I'd like to install Lubuntu 22.04 with bootloader etc. encrypted as far as possible, with working suspend-to-disk, to an old netbook's SSD; no EFI, no other OS.
I found this guide for Ubuntu, but I also read that the Lubuntu-installer would handle FDE completely different, is that true? https://help.ubuntu.com/community/Full_Disk_Encryption_Howto_2019

How should the disk be partitioned on a system without EFI?
Would it be reasonable not to use LVM and just have a swap file on the encrypted partition?
Is it still necessary to use LUKS1 instead of LUKS2 to install GRUB2 like the guide says, or is LUKS1 preferable on devices with low RAM anyway?
Is the recommendation to use a keyfile as safe as having to enter the password twice?